The present invention relates to a seal device for sealing under pressure the inlet or outlet of a high pressure steamer through which fabric to be treated as passed. Textiles, such as cloth or the like, are treated under the conditions of high pressure, high temperature and high humidity in high pressure steamers.
Conventional seal devices of this type are generally composed of a pair of rubber seal rolls extending transversely of the opening to be sealed and disposed in pressed contact with each other. The opening forms an inlet or outlet for fabric to be treated in the drum body of a high pressure steamer. A pair of spaced metal seal rolls are rotatably mounted below the rubber seal rolls and each is disposed in pressed contact with one of the rubber seal rolls for blocking the inlet or the outlet for fabric opening to the drum body.
As the quality of the material to be treated improves the conditions for its treatment at high temperatures and high pressures using such a conventional seal device are required to be such that the internal pressure of the steamer is at more than 5 kg/cm.sup.2 and the heating temperature is about 160.degree. C, in particular, high pressure and high temperature of more than 155.degree. C are indispensable for dyeing polyester material.
According to the conventional seal device shown in FIG. 1, when the internal pressure within drum body 1 of a high pressure steamer is directed against the pressure bearing surfaces a, a occupying nearly one fourth of the peripheral area of the rubber seal rolls 2, 2' and with the conditions, in drum body of the stamer consisting of a pressure of 5 kg/cm.sup.2, a heating temperature of 158.degree. C and with the full width of each of the rolls 2 and 2' being 2000 mm and 1650 mm, respectively, the load (per ton) imparted respectively on the seal rolls 2, 2' is indicated in the following table:
______________________________________ Length of roll to be Width of rolls Width of rolls loaded (cm) 2000 mm 1650 mm ______________________________________ Present seal (1) 2.5 cm 25 ton 20.6 ton (2)13.4 13.4 11.05 (3) 9.2 9.2 7.59 (4) 7.2 7.2 5.94 Lower limit (5) 5.8 5.8 4.78 For reference (6) 5.0 5.0 4.125 ______________________________________
Consequently, with a seal device recently in use the load of about 20 tons is imparted to each of seal rolls causing widening of the nipping action of the rolls in the event that the width of rolls is 1650 mm and the internal pressure of the drum body of the steamer is 5 kg/cm.sup.2, wherefore supporting means for the rubber seal rolls having enough strength to bear against the load of about 20 tons should be utilized in the conventional seal device; equipment as set forth about is not effective for enlarging the structure of the seal device.
Further, when the pressure bearing surfaces increase in the peripheral area of the rubber seal rolls, the surface influenced by high temperature generated within the high pressure steamer naturally increases and, as a result, the surface temperature of the seal rolls is raised. Furthermore, when the heating temperature contacting the rubber seal rolls reaches 140.degree. C, the rubber is hardened causing cracks on the surface of the rolls, whereby the sealing effectiveness is reduced by half.
Moreover, dyestuff for fabric and cloth being treated tends to adhere to the peripheral surface of the rubber seal rolls and to permeate into the inner part of the rolls as a result of the heating treatment, thus the rubber rolls are denaturized that is, deprived of their natural qualities, and, as a result, are unable to provide on an efficacious sealing action for a long period of time.